It's really tempting to say "well I didn't have formal HS programming classes, and I turned out just fine" but it obscures the much larger demographic issue in Computer Science: studies show that when computer science is taught to all kids, those who take that teaching further are far more representative of the general population than if you leave it up to the kids to discover CS on their own.
Given the power that programmers wield in today's world (and the much greater power they're likely to have in tomorrow's) it's increasingly problematic that we're so predominantly male and ethnically-homogenous.